Process of making basic open-hearth steel



Patented May 10, 1927.

UNITED" STATES JULIAN L. SCHUELER, or PEORIA, ILLINOIS.

PROCESS OF MAKING BASIC OPEN-IIEARTH STEEL.

No Drawing.

iron or other carbon giving materials usually needed in charges of this character.

A further object of my process is that the melting of the heat (high in carbon or low in carbon) may be controlled within rather narrow limits.

A further object of my process is the reduction in the amount of fuel necessary to melt the charge.

The foregoing objects are attained by charging the heats as is usual for charges of this character, except that only about half or less of the amount of limestone usually charged is added. On account of the lessened amount of stone charged a considerably less amount of carbon is needed in the bath to bring the stone up, as will be well understood by those skilled in the art. I may, of course, charge burned lime instead of limestone, in which case the amount of carbon is reduced over that necessary with limestone, and it is possible for the heats to be made in lessened time. The amounts to be used will be readily apparent to those skilled in the art from the description of the practice as outlined with limestone given below.

Then, on account of this lessened stone, it is obvious that as soon as the charge melts the limestone will all be up in the slag. Thus a considerable saving of fuel results from the lessened melting time.

With this lessened amount of limestone the slag formed is very thin, so as soon as the heat has melted I add burned lime which quickly brings the slag up to the proper consistency. Then after adding any other furnace additions, such, for example, as spiegel or ferro-manganese, the heat is ready to tap.

For example, in the usual practice limestone is charged, equal to from 9 to 14 per cent of the Weight of the metal charged. In my improved process I charge only 3% to 7 per cent of the weight of the charge, as limestone. Furthermore, if coke is used to fur- Application filed March 27, 1926. Serial No. 98,018..

nish a part of. the carbon by use of my process I cut this from 3.5 per cent of the weight of the charge to 2.5 per cent, a very material reduction. Or if pig iron or cast iron, or both, are usedI may cut these down proportionately (depending on their carbon content) instead of the coke, or I may cut down on allthree in the proportion outlined above. Furthermore, heats of this type, which are usually made in 13 to 14 hours, are made by my process in from 11 to 12 hours. With a furnace using oil asafuel Iam able by my process to cut the consumption of oil from about 56 gallons per ton to about 50 gallonsper ton.- WVhen. using burned lime I charge from 1 to 5 per cent of the weight of the metal charged. Itis obvious, there fore, that I can use either limestone or burned lime and it is, also, obvious to those skilled in the art that when substituting burned lime for limestone I would use less carbon giving materials.

I have found by actualpractice over an extended period of time that the process as described above, and the objects as outlined,

are attained in a very efl'icient manner, and;

the cost of making steel by my process is materially less than that made by the usual and ordinary process.

What I claim is z---- 1. The process of making basic open hearth steel using cold charges, which consists in first charging an insufficient amount of limestone to form a finishing slag with respect to the weight and kind of metal charged, and without removing the slag formed, finally making up the insufficiency of limestone after the charge has melted by the addition of burned lime to form the finishing slag.

2. The process of making basic open hearth steel using cold charges, which consists in first charging an insuflicient amount of limestone .to form a finishing slag, the Weight of the limestone being equivalent to between 3 and 7 per cent with respect to the weight and kind of metal charged, and without removing the slag formed, finally making u I the insufliciency of limestone, after the c arge has melted by the addition of burned lime to form the finishing slag.

3.'The process of making basic open hearth steel using cold charges, which consists in first charging an insufiicient amount of limestone to form a finishing slag with respect to the weight and kind of metal charged, adding a suitable lessened amount of carbon-giving materials to conform to the lessened amount of limestone, and without removing the slag formed, finally making up the insufliciency of limestone after the charge has melted by the addition of burned lime to form the finishing slag.

4. The process of making basic open hearth steel using cold charges, which consists in first charging an insufficient amount of limestone to form a finishing slag, the weight of the limestone being equivalent to between 3% and 7 per cent with respect to the weight and kind of metal charged, adding a suitable lessened amount or carbongiving materials to conform to the lessened amount of limestone, and without removing the slag formed, finally making up the msufliciency of limestone after the charge has melted by the addition of burned lime to form the finishing slag.

5. The process of making basic open hearth steel using cold charges, which consists in first charging an insuiiicient amount of burned lime to form a finishing slag with respect to the weight and kind of metal charged, and Without removing the slag formed, finally making up the insutficiency of burned lime after the charge has melted by a further addition of burned lime to form the finishing slag.

6. The process of making basic open hearth steel using cold charges, which consists in first charging an insutlicient amount of burned lime to form a finishing slag, the weight of the burned lime being equivalent to between 1% and 5 per cent with respect to the weight and kind of metal charged, and without removing the slag formed, iinally making up the insufficiency of burned lime after the charge has melted by a further addition of burned lime to form the finishing slag.

7. The process of making basic open hearth steel using cold charges, which consists in first charging an insufiicient amount of burned lime to form a finishing slag with respect to the weight and kind of metal charged, adding a suitable lessened amount of carbon-giving materials to conform to the lessened amount of burned lime, and without removing the slag formed, finally making up the insufficiency of limestone after the charge has melted by a further addition of burned lime to form the finishing slag.

8. The process of making basic open hearth steel using cold charges, which consists in first charging an insufiicient amount of burned lime to form a finishing slag, the weight of the burned lime being equivalent to between 1 and 5 per cent with respect to the Weightand kind of metal charged, adding a suitable lessened amount of carbon-giving materials to conform to the lessened amount of burned lime, and without removing the slag formed, finally making up the insufiiciency of burned lime after the charge has melted by a further addition of burned lime to form the finishing slag.

JULIAN L. SCHUELER. 

